Abstract: The central cholinergic system has been long implicated in learning and memory processes in mammals. However, the precise role of this system in memory formation in birds remains to be determined. Using a one-trialpassive avoidance task, we demonstrated that inhibition of the central choli nergic system activities by intracranial injection of scopolamine produced amnesia in a dose-dependent manner.The amnesia induced by scopolamine in this task developed between 15-20 minutes after training whenever the drug was administered 15 or 30 minutes before training. Since scopolamine in present doses did not affect disgust reactions, general pecking behavior, and motor behavior as shown in an open field task,the memory effects of scopolamine observed in this study cannot be easily attributed to processes unrelated to memory processing,such as sensorimotor performance and general arousal.These results suggested a specific role of the avian central cholinergic system in the formation of intermediateterm -memory,strongly supportingthe three-stage model of memory formation originally proposed by Gibbs and Ng(1977)

Key words: Scopolamine, One-day-old chick, Intermediate-term memory